Can Bobby Witt Jr. ever be a star if he doesn’t get on base?

Last week on these very digital pages, we explored if Bobby Witt Jr. could reasonably be expected to increase his paltry walk rate from this rookie season. The answer: yes, it could happen, as Marcell Ozuna and Nolan Arenado both stand as recent examples of top prospects who made the big leagues at age-22 and managed to increase their walk rates later in their careers.

Consider this piece, then, a part two of sorts, because there’s another angle here: what are the consequences of Witt failing to increase his on base ability? Can he become a star if he doesn’t get on base much? And just how much does he have to increase his on base percentage for him to have a shot at reasonable stardom?

First, let’s define “star.” It’s a subjective measurement, but I think that most people would define a star as a player who is consistently productive and who is good enough to make a few All-Star Games and maybe grab some MVP votes at some point in their career—the type of player who can, at their peak, carry a team through a tough playoff series. A star also isn’t a flash in a pan, but has a track record of production.

Now, what does that mean in terms of some hard stats? Because this is a Royals blog, let’s take an example of one past Royals star: Alex Gordon. Looking at Fangraphs’ version of Wins Above Replacement, Gordon was worth 2.73 WAR per 150 games played*. That seems about right, as some seasons he played at a 4 WAR level and others he played at a 1 WAR level. Gordon accumulated over 30 WAR across a long career, but around half that is plenty for a player to establish themselves as a star.

*Why am I using WAR per 150 games played? Two reasons: first, it eliminates factors like playing time and injuries that could muddy the waters of our data, as we’re specifically looking at on base ability’s impact on star viability. Second, the shortened 2020 season is a big thorn in our side, and prorating performance across full and shortened seasons gives players proper credit for their production that year.

So, with that in mind, let’s pull up a large group of players who fit those categories: 15 or more career WAR, at least 2.70 WAR per 150 games, both since 2010. This list of comprised of 122 players. It’s not a perfect list and surely includes both snubs as well as unusual inclusions into the definition of “star,” but it’s pretty good. Here are the top and bottom player in the “star” list, as well as the median player and two players who represent the halfway point between the median and the top or bottom, respectively:

There are a few takeaways from this subset of the broader list. First, there are multiple ways to become a star. Jose Altuve built his kingdom around hitting for average, while Joey Gallo became a star through the Three True Outcomes of hitting homers, walking, and striking out (Gallo has ended over 55% of his career plate appearances with one of those three outcomes, a truly bonkers statistic). Mike Trout is Mike Trout, while Denard Span is the borderline star whose main production was through reliable defense and baserunning skill.

But the data lays out something else that’s uncomfortable: in this set of players, the median OBP is .346. This is a huge difference from Witt’s current OBP, which has dipped below .290 in a tribute to Witt’s fellow low-OBP and high-power teammate, Salvador Perez. Furthermore, the median “star” walk rate is north of 9%, almost double Witt’s current walk rate.

Are there any players who hit “star” status who had low OBPs? Some. Here are the 10 players with the lowest OBP out of our set of players:

The first thing that you’ll notice is that some of these players aren’t really stars; this shows the limitations of my somewhat arbitrary requirements. But the other thing that you’ll notice is that these players play premium positions, are defensive wizards, or both. Travis d’Arnaud and Mike Zunino are catchers. Andrelton Simmons, Kevin Kiermaier, and Byron Buxton have all won the Platinum Glove award, of which there is one recipient per league per year. Javier Baez and Jimmy Rollins are Gold Glove winners. Witt does not have this feather in his cap to say the least.

This subset of our player list does offer a glimpse into some hope that Witt still has it in him to be a legitimate star. Buxton and Tim Anderson spent their respective first few seasons showing flashes but, ultimately, failing to live up to expectations. Buxton slashed .230/.285/.387 over his first four seasons and 1074 plate appearances, accruing 2.8 WAR per 150 games due to his defense. Anderson slashed .258/.286/.411 over his first three seasons and 1643 PA, accruing 2.1 WAR per 150 games.

Buxton and Anderson then became totally different players in their age-25 and age-26 seasons, respectively. Buxton has slashed .258/.316/.558 over his past four seasons, accruing a whopping 6.6 WAR per 150 games. Meanwhile, Anderson has slashed .318/.347/.474 over his last four seasons, accruing 5.5 WAR per 150 games.

But, of course, there are other results in addition to “star” that can happen, and Witt’s on base ability is going to be a huge driving factor in it. I wanted to see what the average outcome trends were for players when it comes to their on OBP and their overall production were. So, I pulled all players since 2010 with at least 1500 plate appearances and plotted them on a graph, specifically comparing WAR/150 and OBP.

The correlation between OBP and WAR is pretty high considering all the factors that go into WAR, such as defense, baserunning, positional adjustments, and literally every other kind of offensive statistic. This makes sense, though, because getting on base is the single most important thing you can do. As I’ve explained before: outs are best understood as a finite resource. The batters who use up less of that resource are more valuable than ones that use up more of it, even if they do other flashy and impressive things.

Otherwise, there are a few soft OBP requirements that show up in the data, and the main one can be found at about the .330 OBP level. None of the nearly 500 players in this data set were below replacement level if they achieved a .330 OBP; likewise, the 4+ WAR players start regularly showing up at about the .330 OBP line.

No, there’s nothing magical about the .330 OBP, just as there’s nothing magic about a .300 batting average or a .200 ISO. Witt can be a star if he doesn’t get there. Notably, Witt also doesn’t have to put up a double-digit walk rate to reach that mark. Witt can achieve a .330 OBP via a modest increase in walk rate paired with an increase in batting average.

Can Witt ever be a star if he doesn’t get on base? Technically, yes. But to be the kind of star that validates his extreme hype? Not really. That should be the main thing he works on in the offseason.